Semi-rigid duct system

Abstract

A duct system is formed from a plurality of tubular sections each formed from a flexible panel with tapering sides. Inner and outer joiner plates are attached to one side edge and the second side edge is inserted in the recess between the plates and fastened such that each section has a first open end and a second slightly larger open end. Anchors are spaced around each end of each tubular section. The first end of each tubular section is inserted into the larger second end of an adjacent tubular section and an end pulling element is connected between the anchors on adjacent sections an operated to draw the connected first and second anchors together to make a substantially air tight seal between the tubular sections.

The invention claimed is: 
     
       1. A duct system comprising:
 a plurality of tubular sections connected together, each tubular section comprising: 
 a flexible panel having a length between first and second end edges thereof, a first width between first and second side edges at the first end edge, and second width between first and second side edges at the second end edge, wherein the first width is less than the second width; 
 inner and outer joiner plates attached to inner and outer faces of the flexible panel along the first side edge and extending outward from the first side edge such that a recess is formed between the inner and outer joiner plates, and wherein the second side edge is inserted into the recess and fastened in the recess to form the flexible panel into the tubular section with the inner joiner plate on an interior of the tubular section and the outer joiner plate on an exterior of the tubular section; 
 wherein each tubular section has an open substantially circular first end with a first diameter at the first end edge of the panel and an open substantially circular second end with a second diameter at the second end edge of the panel, and wherein the first diameter is less than the second diameter; 
 a plurality of first end anchors spaced around each tubular section at a first anchor distance from the first end of the tubular section; 
 a corresponding plurality of second end anchors spaced around each tubular section at a second anchor distance from the second end of the tubular section; 
 wherein the first end of each tubular section is inserted into the second end of an adjacent tubular section such that a portion of the outer face of each tubular section proximate to the first end thereof bears against a portion of the inner face of the adjacent tubular section proximate to the second end thereof; 
 a plurality of end pulling elements, each end pulling element connected between one of the first anchors on one tubular section and one of the second anchors on the adjacent tubular section, and each end pulling element operative to exert a force drawing the connected first and second anchors together and pushing the outer face of the one tubular section against the inner face of the adjacent tubular section; 
 a first reinforcing ring extending around each tubular section adjacent to the first end anchors such that the first end anchors are between the first end of the tubular section and the first reinforcing ring; and 
 a second reinforcing ring extending around each tubular section adjacent to the second end anchors such that the second end anchors are between the second end of the tubular section and the second reinforcing ring, wherein an inner diameter of the first and second reinforcing rings substantially corresponds to an outer diameter of the tubular section. 
 
     
     
       2. The system of  claim 1  wherein each second side edge is fastened in the corresponding recess by a plurality of side pulling elements, each side pulling element extending over the outer joiner plate and connected to side anchors attached to the tubular section on each side of the outer joiner plate; each side pulling element operative to exert a force drawing the second side edge into the recess. 
     
     
       3. The system of  claim 1  comprising a lock tab extending from the second side edge of each flexible panel, and a corresponding lock notch defined in the first side edge of each flexible panel, the lock tab and lock notch configured such that when the second side edge is inserted into the recess, the lock tab flexes as the lock tab enters the lock notch and locks into the lock notch. 
     
     
       4. The system of  claim 3  wherein the lock tab slopes inward from the outer face of the flexible panel toward the inner face of the flexible panel. 
     
     
       5. The system of  claim 1  wherein the outer joiner plate extends from the first side edge of the flexible panel a greater distance than the inner joiner plate. 
     
     
       6. The system of  claim 1  wherein outer edges of the inner and outer joiner plates adjacent to the recess are chamfered. 
     
     
       7. The system of  claim 1  wherein the first reinforcing ring comprises two half rings fastened to each other after the second side edge is inserted into the recess to form the tubular section. 
     
     
       8. The system of  claim 1  wherein the first end edge of each flexible panel comprises a shoehorn element extending from a middle portion of the first end edge. 
     
     
       9. The system of  claim 1  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section such that first anchors on each tubular section are substantially aligned with second anchors on the adjacent tubular section. 
     
     
       10. The system of  claim 1  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section such that the joiner plates on each tubular section are substantially aligned with the joiner plates on the adjacent tubular section. 
     
     
       11. The system of  claim 1  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section at an insertion distance substantially equal to the first anchor distance, and wherein on each tubular section, the outer joiner plate extends from a first outer plate end thereof located the insertion distance from the first end of the tubular section to a second outer plate end thereof located at the second end of the tubular section. 
     
     
       12. The system of  claim 11  wherein on each tubular section, the inner joiner plate extends from a first inner plate end thereof located at or in proximity to the first end of the tubular section to a second inner plate end thereof located the insertion distance from the second end of the tubular section. 
     
     
       13. The system of  claim 1  comprising a sealing band around the second end of each tubular section, and a band tightener operative to exert a tightening force on the sealing band to force the inner face of the second end of each tubular section against the outer face of the first end of the adjacent inserted tubular section. 
     
     
       14. The system of  claim 1  wherein at least one end pulling element is provided by a resilient strap. 
     
     
       15. The duct system of  claim 1  wherein the force exerted by each end pulling element to push the outer face of the one tubular section against the inner face of the adjacent tubular section forms a substantially air tight seal between the outer face of the one tubular section and the inner face of the adjacent tubular section. 
     
     
       16. A method of providing a duct system, the method comprising:
 forming a plurality of tubular sections, each tubular section formed by:
 providing a flexible panel having a length between first and second end edges thereof, a first width between first and second side edges at the first end edge, and second width between first and second side edges at the second end edge, wherein the first width is less than the second width; 
 attaching inner and outer joiner plates to inner and outer faces of each panel along the first side edge such that the joiner plates extend outward from the first side edge such that a recess is formed between the inner and outer joiner plates; 
 inserting the second side edge into the recess and fastening the second side edge in the recess to form the panel into the tubular section with the inner joiner plate on an interior of the tubular section and the outer joiner plate on an exterior of the tubular section; 
 
 wherein each tubular section has an open substantially circular first end with a first diameter at the first end edge of the panel and an open substantially circular second end with a second diameter at the second end edge of the panel, and wherein the first diameter is less than the second diameter; 
 attaching a plurality of first end anchors spaced around each tubular section at a first anchor distance from the first end of the tubular section; 
 attaching a corresponding plurality of second end anchors spaced around each tubular section at a second anchor distance from the second end of the tubular section; 
 inserting the first end of each tubular section into the second end of an adjacent tubular section; 
 connecting an end pulling element between each of the first and second anchors and operating each end pulling element to exert a force drawing the connected first and second anchors together such that the first end of each tubular section is forced into the second end of the adjacent tubular section and such that a portion of the outer face of each tubular section proximate to the first end thereof bears against a portion of the inner face of the adjacent tubular section proximate to the second end thereof; and 
 wherein the circular shape of the first and second open ends is maintained by placing a first reinforcing ring tightly around each tubular section adjacent to the first anchors such that the first anchors are between the first end of the tubular section and the first reinforcing ring, and a second reinforcing ring tightly around each tubular section adjacent to the second anchors such that the second anchors are between the second end of the tubular section and the second reinforcing ring. 
 
     
     
       17. The method of  claim 16  comprising forming each tubular section such that each tubular section is substantially airtight from the first end thereof to the second end thereof, and inserting each tubular section into the adjacent tubular section such that the connection between the tubular sections is substantially airtight. 
     
     
       18. A duct system comprising:
 a plurality of tubular sections connected together, each tubular section comprising: 
 a flexible panel having a length between first and second end edges thereof, a first width between first and second side edges at the first end edge, and second width between first and second side edges at the second end edge, wherein the first width is less than the second width; 
 inner and outer joiner plates attached to inner and outer faces of the flexible panel along the first side edge and extending outward from the first side edge such that a recess is formed between the inner and outer joiner plates, and wherein the second side edge is inserted into the recess and fastened in the recess to form the flexible panel into the tubular section with the inner joiner plate on an interior of the tubular section and the outer joiner plate on an exterior of the tubular section; 
 wherein each tubular section has an open substantially circular first end with a first diameter at the first end edge of the panel and an open substantially circular second end with a second diameter at the second end edge of the panel, and wherein the first diameter is less than the second diameter; 
 a plurality of first end anchors spaced around each tubular section at a first anchor distance from the first end of the tubular section; 
 a corresponding plurality of second end anchors spaced around each tubular section at a second anchor distance from the second end of the tubular section; 
 wherein the first end of each tubular section is inserted into the second end of an adjacent tubular section such that a portion of the outer face of each tubular section proximate to the first end thereof bears against a portion of the inner face of the adjacent tubular section proximate to the second end thereof; and 
 a plurality of end pulling elements, each end pulling element connected between one of the first anchors on one tubular section and one of the second anchors on the adjacent tubular section, and each end pulling element operative to exert a force drawing the connected first and second anchors together and pushing the outer face of the one tubular section against the inner face of the adjacent tubular section; 
 wherein the first end edge of each flexible panel comprises a shoehorn element extending from a middle portion of the first end edge. 
 
     
     
       19. The system of  claim 18  wherein each second side edge is fastened in the corresponding recess by a plurality of side pulling elements, each side pulling element extending over the outer joiner plate and connected to side anchors attached to the tubular section on each side of the outer joiner plate; each side pulling element operative to exert a force drawing the second side edge into the recess. 
     
     
       20. The system of  claim 18  comprising a lock tab extending from the second side edge of each flexible panel, and a corresponding lock notch defined in the first side edge of each flexible panel, the lock tab and lock notch configured such that when the second side edge is inserted into the recess, the lock tab flexes as the lock tab enters the lock notch and locks into the lock notch. 
     
     
       21. The system of  claim 20  wherein the lock tab slopes inward from the outer face of the flexible panel toward the inner face of the flexible panel. 
     
     
       22. The system of  claim 18  wherein the outer joiner plate extends from the first side edge of the flexible panel a greater distance than the inner joiner plate. 
     
     
       23. The system of  claim 18  wherein outer edges of the inner and outer joiner plates adjacent to the recess are chamfered. 
     
     
       24. The system of  claim 18  comprising a reinforcing ring extending around each tubular section. 
     
     
       25. The system of  claim 24  wherein the reinforcing ring comprises two half rings fastened to each other after the second side edge is inserted into the recess to form the tubular section. 
     
     
       26. The system of  claim 18  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section such that first anchors on each tubular section are substantially aligned with second anchors on the adjacent tubular section. 
     
     
       27. The system of  claim 18  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section such that the joiner plates on each tubular section are substantially aligned with the joiner plates on the adjacent tubular section. 
     
     
       28. The system of  claim 18  wherein the first end of each tubular section is inserted into the second end of the adjacent tubular section at an insertion distance substantially equal to the first anchor distance, and wherein on each tubular section, the outer joiner plate extends from a first outer plate end thereof located the insertion distance from the first end of the tubular section to a second outer plate end thereof located at the second end of the tubular section. 
     
     
       29. The system of  claim 28  wherein on each tubular section, the inner joiner plate extends from a first inner plate end thereof located at or in proximity to the first end of the tubular section to a second inner plate end thereof located the insertion distance from the second end of the tubular section. 
     
     
       30. The system of  claim 18  comprising a sealing band around the second end of each tubular section, and a band tightener operative to exert a tightening force on the sealing band to force the inner face of the second end of each tubular section against the outer face of the first end of the adjacent inserted tubular section. 
     
     
       31. The system of  claim 18  wherein at least one end pulling element is provided by a resilient strap.